<!DOCTYPE html>
<html>
<head>
    <title>Add Example 1</title>
    <script type="text/javascript">
    
        var result1 = 5 + 5;     //two numbers
        alert(result1);           //10
        var result2 = 5 + "5";   //a number and a string
        alert(result2);           //"55"

       
    </script>

</head>
<body>
  
</body>
</html>